1. Field of the Invention
This invention relates to a turret lathe, more particularly to a turret lathe with a clutch for operating between chamfering and turning operation modes.
2. Description of the Related Art
FIG. 1 illustrates a conventional turret lathe that includes a bed 11, a headstock 12 mounted on the bed 11, a driving unit (not shown) mounted on the bed 11, a spindle journalled to the headstock 12 and driven by the driving unit, a chuck 14 mounted on the spindle and adapted to hold a workpiece (not shown), a saddle 13 mounted on the bed 11, a first slide 15 mounted slidably on the saddle 13 and slidable in a longitudinal direction toward the chuck 14, a second slide 16 mounted on the first slide 15 and slidable in a transverse direction relative to the longitudinal direction, a turning seat 17 mounted on one end of the second slide 16 and opposite to the headstock 12, a turret 18 mounted securely on the turning seat 17, a turning tool (not shown) mounted on the turret 18 for turning the workpiece, a chamfering seat 19 mounted on the other end of the second slide 16, a driven shaft (not shown) journalled to the chamfering seat 19, a chamfer tool 102 mounted on the driven shaft so as to co-rotate therewith for chamfering the workpiece, a transmission unit 10 connected to the driven shaft, and a clutch 101 that is operable between a chamfering operation mode, in which the clutch 101 connects the transmission unit 10 to the driving unit, thereby permitting co-rotation of the spindle and the driven shaft during a chamfering opeation, i.e., co-rotation of the chamfer tool 102 and the workpiece, and a turning operation mode, in which the clutch 101 disconnects the transmission unit 10 from the driving unit, thereby avoiding co-rotation of the spindle and the driven shaft during a turning operation. In the chamfering operation, the chamfer tool 102 is moved toward the workpiece by sliding the first slide 15 in the longitudinal direction and the second slide 16 in the transverse direction toward the workpiece, and the clutch 101 is adjusted to the chamfering operation mode to permit co-rotation of the chamfer tool 102 and the workpiece. In the turning operation, the turning tool is moved toward the workpiece in a manner similar to that of the chamfer tool 102, and the clutch 101 is adjusted to the turning operation mode to avoid rotation of the driven shaft when the workpiece rotates.
The conventional turret lathe is disadvantageous in that a turning seat 17 and a chamfering seat 19 are required for mounting of the turning tool and the chamfering tool 102, respectively, which complicates the structure of the conventional turret lathe and which increases the manufacturing cost.